physio lab - renal system

kidneys, ureters, urinary bladder, and the urethra

what makes up the urinary system

by removing unwanted substances and recycling others

how is the urinary system constantly working to maintain the purity and health of the body’s fluids?

homeostasis … plasma …. metabolic … ions … water

the kidneys contribute to ___ by regulating ___ composition through the elimination of ___ wastes, ___, excess ___, and ___

retroperitoneal … posteriorly

the kidneys are ___ organs located ___ to the vertebral column

because the liver pushes the right kidney downwards

why is the left kidney higher than the right?

• volume, composition, pH

• ammonia

• gluconeogenesis

• osmolarity … aquaporin … C.D

regulation of the kidney:

• v___, c___, and ___ of the body fluids

• acid base homeostasis via the production of ___

• energy metabolism via ___ during fasting conditions

• plasma ___ through the control of ___ receptors in the ___

• metabolic wastes

• vitamin D3

• erythropoietin … renin

functions of the kidney:

• detoxification of ___ through excretory mechanisms

• conversion of ___ to its active form

• synthesis and conversion of important hormones like ___ and ___

fatigue and sweets craving

what is the result of a vitamin D3 deficiency

renal papilla

the medulla pyramids have an apex aka the ___

the superficial cortex

what is deep to the fibrous capsule

papilla … minor … major … pelvis … ureter

nephrons of the medulla drain into → apex/___→ ___ calyx → ___calyx → renal ___→ ___→ bladder → urethra

segmental … interlobar …interlobular …glomerulus … peritubular … vasa recta … interlobular … interlobar … segmental

renal blood flow:

renal a. → ___ a. → ___ a. → arcuate a. → ___ a. → afferent arteriole → ___→ efferent arteriole → ___ capillaries → ___ → ___ v. → arcuate v. → ___ v. → ___ v. → renal v.

filtration

what happens between the glomerulus and the glomerular capsule

secretion and reabsorption

what happens between the peritubular capillaries and the PCT

secretion and reabsorption

the loop of henle and DCT play roles in…?

filtration

the first stage of urine production that happens in the renal corpuscle

filtrate

made of water, electrolytes, and organic molecules; enters the glomerular capsule, and normally 180L/day is made

reabsorption

movement of substances from the renal tubules into capillaries

• happens in both the PCT and DCT along w/ descending/ascending limbs

secretion

movement of substances from the capillaries into renal tubules

• happens in the PCT and DCT

glomerular filtration

initial stage for urine formation

porous … blood

the endothelium of glomerular capillaries is very ___ in order to allow fluid, waste products, ions, glucose, and amino acids to pass from ___ into the capsule

blood cells … proteins … vasa recta

glomerular capillaries block out big molecules like ___ and ___ so they end up staying in the blood and exiting via the ___

filtrate

the stuff that gets squeezed out of the blood into the capsule and then sent along the renal tubule

glomerular filtration rate (GFR)

volume of filtrate produced by both kidneys per minute

• physiological indicator of renal funciton

• determined by starlings pressures

higher … filtration

we want oncotic pressure of the glomerular capillaries to be ___ than the pressure of the bowman’s space for ___ to occur

decrease … minimal

constriction of afferent arteriole leads to a ___ in pressure → ___ filtration

no

an equal pressure between the glomerular cap. and bowmans space → ___ filtration

back up … increased …. filtration

constriction of the efferent arteriole → back up blood → increased pressure in glomerular cap. → filtration

cuboidal epithelial cells … mitochondria … Na … active

the cell walls of PCT are made of ___ w/ ___ to power ___ pumps from the filtrate using ___ transport

surface area … reabsorb

microvilli of PCT is used to increase ___ to help ___ as much of good stuff

glucose, amino acids, proteins, vitamins, lactate, urea, uric acid, Na, K, Ca, Mg, Cl, HCO3, and H2O

whats reabsorbed in the PCT via Na cotransport

PCT

the majority of renal reasborption happens in the…?

67 … isosmotic … ECF composition … homeostasis

___% of Na and H20 are rebabsorbed in equal proportions or ___ which is important for maintenance of chemical intergrity of ___ and ___

renal threshold of glucose

200mg/dL

• <200mg/dL → 100% glucose reabsorption

• 
  

nephron

main functional unit of the kidney responsible for urine fomration

cortical nephron

nephron mostly in the cortex and has shorter LOH

• 80-85% of nephrons in humans

juxtamedullary nephrons

nephrons mostly in the medulla that have longer LOH that extend into the renal medulla

• 15-20% of nephrons in humans

corpuscle … bowmans … glomerulus

nephron is composed of renal ___ = ___capsule + ___

• PCT

• LOH

• DCT

3 parts of the renal tubule:

juxtamedullary nephrons … greater

the ___ have longer LOH → ___ counter-current multiplication

permeable … build up

the descending LOH is ___ to H2O → ___ salt concentration in filtrate

impermeable … out of

the ascending LOH is ___ → pumping of salt ___the body

counter-current multiplication

high concentration of salt in the interstitial fluid of the medulla causes water to passively flow in the descending portion via osmosis

Na, Cl, HCO3, and H2O

what is reabsorbed from the DCT

NH4 - ammonium

what is secreted in the DCT

aldosterone … steroid

in the DCT, Na reabsorption is regulated by ___ (___ hormone from the adrenal cortex)

PTH … low

in the DCT, Ca reabsorption is stimulated by the ___ when Ca is ___

collecting duct

what does the DCT empty filtrate into?

the collecting duct

duct that contains aquaporins which aid in the reabsorption of water into the blood

• Na reabsorbed

• K excreted

what is reabsorbed and excreted via the collecting duct

important hormones/hormonal systems in the renal system

• renin-angiotensin-aldosterone system

• aldosterone

• ADH/vasopressin

low … juxtaglomerular … renin … extraglomerular mesangial

renin-angiotensin-aldosterone system:

• ___ blood volume activates the ___ apparatus to secrete ___ (via ___ mesangial cells)

I … angiotensin converting enzyme … II

pathway of renin in the renin-angiotensin-aldosterone system:

• renin → angiotensin ___ → ___ (ACE) → angiotensin __

angiotensin II

what causes the release of aldosterone from the adrenal cortex?

• Na … DCT … collecting duct

• water … sodium

• thirst

• volume … pressure

aldosterone:

• promotes ___ reabsorption in the ___ and ___

• promotes retention of ___ and ___

• stimulates ___

• increases blood ___→ increase in blood ___

hyperosmotic/concentrated … less .. stays

presence of ADH → ___ urine → ___ urine bc H2O ___in the body

hyposmotic/diluted … more … aquaporins

absence of ADH → ___ urine → ___ urine bc there are no ___ make H2O exit

increases … DCT/collecting ducts … aquaporins

ADH ___ the permeability of H2O of the ___ and ___ by adding ___

aquaporins

the DCT and collecting duct are normally impermeable to water, so ADH increases their permeability by adding these!

• when added, they increase water reabsorption and retention to decrease urine volume

urethra

sphincters seperated the bladder from the …?

• involuntary: internal sphincter

• voluntary: external sphincter

  • pudendal: S2-4

what sphincters are under involuntary and voluntary control?

• full

• urgency

• involuntary

Urine volume:

• 150-200 mL - bladder feels ___

• 300-400 mL - sense of ___

• >600 mL - ___ urination

intercourse drives bacteria from vagina/anus through opening of the short urethra

what are UTI’s most common in sexually active women?

they kill the natural healthy bacteria → allow pathogenic bacteria to colonize

how does spermicides (on condoms) magnify the problem of UTIs being common in sexually active women?

• burning during micturition

• urgency and fequency

• fever

• cloudy/blood tinged urine

UTI symptoms include

bladder weakness, incontinence, urine retentions, and poor bladder emptying

why are elders susceptible to UTIs?

• mental changes

• confusion

UTI in the elderly symptoms

renal calculi

kidney stones

• 4 diferent types but calcium oxalate is the most common

• causes severe pain

• family history

• chronic dehydration

• obesity

• diets high in protein/salt

risk factors of kidney stones

urine … intrarenal

stones <5 mm in diameter might pass through w/o intervention

• stones >5mm become lodged in the ureter → block of ___ and increase in ___ pressure

lithotripsy

uses shock waves to break up stones